In recent years, environmental pollution of global scale, such as global warming, ozone layer depletion, acid rain, is an international problem. For this reason, it has become an urgent need to establish measures against environmental pollution, and currently, various emission regulations are being carried out in each country from the point of view of environmental protection. Among them, since the problem of discharge into the atmosphere of organic solvents (VOC) is critical, reduction of organic solvents (de-VOC) is underway under enhanced VOC emission-control regulations, particularly in the paint industry.
Heretofore, VOC have been used for paints, but as de-VOC has been promoted, more recently, it has become common to widely use powder paints presenting little environmental impact, which contain no VOC at all and thus require no exhaust treatment or wastewater treatment and which can further be recovered and reused.
Previously, as raw materials for powder paints, acrylic resins, polyester resins or epoxy resins have been primarily used.
However, cured films formed by the powder paints containing them as raw materials, are not sufficient in weather resistance.
Under the circumstances, attention has been drawn to a fluororesin as a resin which can be used for a powder paint and is excellent in weather resistance.
As a powder paint composition containing a fluororesin, for example, a powder coating composition comprising a hydroxy group-containing fluororesin and a polyuretdione curing agent or a blocked isocyanate curing agent may be mentioned (Patent Document 1).